8 Common Questions about Deer Mice

The deer mouse may be cute, but it can be deadly. Thomas Kitchin & Victoria Hurst/First Light/Getty Images

As cute as it appears to be, the deer mouse (Peromyscus maniculatus) can actually be a very deadly creature. As a carrier of Hantavirus, this mouse can be held responsible for serious human disease and even death, including three deaths at Yosemite Park in 2012.

What Does the Deer Mouse Look Like?

With big eyes and prominent, leaf-like ears, the deer mouse is a deceptively cute creature. Its head and body measure about 2 to 3 inches long, and its tail is just as long as its body.

Why Is It Called a Deer Mouse?

Because it somewhat resembles a very small deer: the mouse's upper body is grey to reddish brown, its underbelly and legs are white, and its tail has two colors: dark on top and white on the sides and bottom.

Where Do Deer Mice Live?

Although the deer mouse prefers woodlands and rural areas, it will also make its home in urban areas/cities. It may live about anywhere it finds concealed harborage and nearby food, such as in underground burrows, brush piles, and weedy/grassy areas; under logs, stumps, or rocks; in abandoned dens of other animals and in the natural cavities of trees.

If Deer Mice Are so Cute and Usually Live in the Woods, Why Are They a Problem?

This cute-looking rodent is the primary carrier of hantavirus in the U.S. Hantavirus is transmitted primarily through the inhalation of contaminated air as well as through contact with mouse urine, feces, saliva of infected rodents.

So Why Is Hantavirus so Bad?

Since it was first recognized in 1993, more than half the people who have been diagnosed with Hantavirus Pulmonary Syndrome (HPS) have died from the disease. And there is still no recognized cure. During the summer of 2012, eight people contracted the disease at Yosemite National Park, three of whom had died by early fall.

Is the Deer Mouse the Only Mouse That Carries the Disease?

No, Hantavirus is also carried by:

The white-footed mouse - closely resembling the deer mouse, it is found in many areas of the U.S., including the east coast from the South up through Southern New England, the Midwest and the West, as well as Mexico. Like the deer mouse, this mouse prefers concealed harborage, but it will also live in open areas.

The cotton rat - With a head and body that measures 5 to 7 inches in length and its tail adding another 3 to 4 inches, this rodent is much larger than the deer mouse. In the U.S., this rat is found primarily in the Southeast states, and it prefers to live in areas that are overgrown with weeds, shrubs or tall grass.

The rice rat - Though smaller than the cotton rat, the rice rat is still larger than the deer mouse. As its name would indicate, this semi-aquatic rat prefers areas such as those of rice paddies: wet and marshy. In the U.S., it is found primarily in the Southeast.

So What Can I Do to Prevent Hantavirus?

The most important thing you can do to prevent contracting hantavirus is to avoid contact with these mice, areas in which they are known to be, and areas where infestations are or have been present.

In addition, you can take steps to prevent rodents in and around your home:

Eliminate or minimize contact with rodents in your home, workplace, or campsite.

Seal holes and gaps in your home or garage.

Place traps in and around your home to decrease rodent infestation.

Clean up litter and piles where rodents like to live and breed.

Clean up and/or put away exposed food to make it less attractive and less accessible to rodents (and other pests).